This invention relates to tethered balloons used for aerial film or video recording, advertisements, shows and other activities done in the air and more particularly to tethered balloons used at relatively low altitudes (between 30 and 150 m).
Telecasting of ball games, film or video recording, advertisements, shows and other activities are often carried out at a fixed point in the air. These activities are carried out by using helicopters, airships and tethered balloons that can remain floating in the air. However, helicopters cannot remain floating at any given point in the air for a prolonged period of time. Besides, they produce large noises and vibrations. Airships and tethered balloons cannot be used when strong winds are blowing (at a speed of, for example, 7 meters per second or above) because they roll and pitch considerably. Tethered balloons usually employ a connecting net so that the tethering load acting on the balloon proper (or the floating power of the balloon) does not concentrate at the joint where the balloon proper and tether are connected together. The connecting net is a cone formed by multiple connecting ropes that are attached to the balloon proper at the bottom of the cone. The stationary satellite balloon contrived by the inventor is an example of the tethered balloons of the type just described (see Japanese Provisional Patent Publication No. 198188 of 1996).
Conventional tethered balloons have a connecting net that extends vertically down. In the presence of strong winds, therefore, they sway back and forth (in the direction of wind), lose their stability and sometimes crash against the ground. The connecting net extending vertically down gets into the field of vision of the camera used for bird's-eye view film or video recording, as well.